Downloading Images from a Website with Javascript and cheerio

In this article, we will learn how to use Javascript and the cheerio library to download all the images from a Wikipedia page.

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Overview

The goal is to extract the names, breed groups, local names, and image URLs for all dog breeds listed on this Wikipedia page. We will store the image URLs, download the images and save them to a local folder.

Here are the key steps we will cover:

1. Import required modules
2. Send HTTP request to fetch the Wikipedia page
3. Parse the page HTML using cheerio
4. Find the table with dog breed data using a CSS selector
5. Iterate through the table rows
6. Extract data from each column
7. Download images and save locally
8. Print/process extracted data

Let's go through each of these steps in detail.

Imports

We need these modules:

const request = require('request');
const cheerio = require('cheerio');
const fs = require('fs');

Send HTTP Request

To download the web page:

const url = '<https://commons.wikimedia.org/wiki/List_of_dog_breeds>';

request({
  url: url,
  headers: {
    'User-Agent': 'Mozilla/5.0'
  }
}, (error, response, html) => {

  // Parse HTML

});

We make a GET request and provide a user-agent header.

Parse HTML

To parse the HTML:

const $ = cheerio.load(html);

The cheerio object allows querying the document.

Find Breed Table

We use a CSS selector to find the table element:

const table = $('table.wikitable.sortable');

This selects the

Iterate Through Rows

We loop through the rows:

table.find('tr').slice(1).each((i, elem) => {

  // Extract data

});

We slice to skip the header row.

Extract Column Data

Inside the loop, we extract the column data:

const cells = $(elem).find('td, th');

const name = $(cells[0]).find('a').text().trim();
const group = $(cells[1]).text().trim();

const localName = $(cells[2]).find('span').text().trim() || '';

const img = $(cells[3]).find('img');
const photograph = img.attr('src') || '';

We use text() for text and attr() for attributes.

Download Images

To download and save images:

if (photograph) {

  request(photograph).pipe(fs.createWriteStream(`dog_images/${name}.jpg`));

}

We pipe the image stream directly to a file.

Store Extracted Data

We store the extracted data:

names.push(name);
groups.push(group);
localNames.push(localName);
photographs.push(photograph);

The arrays can then be processed as needed.

And that's it! Here is the full code:

// Imports
const request = require('request');
const cheerio = require('cheerio');
const fs = require('fs');

// Arrays to store data
let names = [];
let groups = [];
let localNames = [];
let photographs = [];

// Fetch HTML
const url = '<https://commons.wikimedia.org/wiki/List_of_dog_breeds>';

request({
  url: url,
  headers: {
    'User-Agent': 'Mozilla/5.0'
  }
}, (error, response, html) => {

  // Load HTML
  const $ = cheerio.load(html);

  // Find table
  const table = $('table.wikitable.sortable');

  // Iterate rows
  table.find('tr').slice(1).each((i, elem) => {

    // Get cells
    const cells = $(elem).find('td, th');

    // Extract data
    const name = $(cells[0]).find('a').text().trim();
    const group = $(cells[1]).text().trim();

    const localName = $(cells[2]).find('span').text().trim() || '';

    const img = $(cells[3]).find('img');
    const photograph = img.attr('src') || '';

    // Download image
    if (photograph) {

      request(photograph).pipe(fs.createWriteStream(`dog_images/${name}.jpg`));

    }

    // Store data
    names.push(name);
    groups.push(group);
    localNames.push(localName);
    photographs.push(photograph);

  });

});

This provides a complete Javascript solution using cheerio to scrape data and images from HTML tables. The same approach can apply to many websites.

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